Skill points VS Trait points
You can get materials needed for Mystic Forge recipes using skill points. Trait points don’t accumulate because build balancing.
(edited by luxymonsteri.1078)
Gaining trait points is a form of vertical progression. When a level 20 character has 5 more trait points than a level 15 character, there are multiple ways to spend those extra points, but no matter how it does so, it is strictly stronger than if it did not have or spend those 5 points. Gaining skill points is primarily a form of horizontal progression. Spending 30 skill points will teach my mesmer mass invisibility, but in order to use it I have to unequip time warp, and that may leave me less powerful overall.
Increasing vertical progression creates a grind where everyone rushes to be as powerful as possible so as to not be at a disadvantage. Increasing horizontal progression gives people something to aim for without leaving them at a significant disadvantage until they reach it.
Ultimately, gaining trait points is more similar to unlocking skill slots than to gaining skill points, and you’ll note that skill slots max out at level 30.